Upgrade to current JSHint

This also allows us to move our settings to .jshintrc for better IDE &
command-line integration - simply type "jshint" in the directory and it
will use the same options.

.jshintrc

@@ -0,0 +1,14 @@
+{
+    "browser": true,
+    "curly": true,
+    "eqeqeq": false,
+    "loopfunc": false,
+    "noarg": true,
+    "trailing": true,
+    "undef": true,
+    "unused": true,
+
+    "globals": {
+        "OpenSeadragon": true
+    }
+}

Gruntfile.js

@@ -147,18 +147,7 @@ module.exports = function(grunt) {
         },
         jshint: {
             options: {
-                browser: true,
+                jshintrc: '.jshintrc'
-                curly: true,
-                eqeqeq: false,
-                loopfunc: false,
-                noarg: true,
-                trailing: true,
-                undef: true,
-                unused: true,
-
-                globals: {
-                    OpenSeadragon: true
-                }
             },
             beforeconcat: sources,
             afterconcat: [ distribution ]

package.json

@@ -6,7 +6,7 @@
     "grunt": "~0.4.0",
     "grunt-contrib-compress": "~0.5.0",
     "grunt-contrib-concat": "~0.1.2",
-    "grunt-contrib-jshint": "~0.1.1",
+    "grunt-contrib-jshint": "~0.6.0",
     "grunt-contrib-uglify": "~0.2.2",
     "grunt-contrib-qunit": "~0.2.0",
     "grunt-contrib-connect": "~0.1.2",